JPS6282501A - Tape guide drum for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To mount many magnetic heads on a drum having an extremely small diameter by providing two pairs of rotary transformers to a rotary member and performing the wiring among those transformers and their corresponding magnetic heads along a rotary shaft. CONSTITUTION:Two pairs of rotary transformers are provided. One of these pairs of transformers includes a rotary side transformer 3 and a fixed side transformer 5 which are opposite to each other under a magnetic head. While the other pair consists of a rotary side transformer 14 and a fixed side rotary transformer 13 which are opposite to each other at a place lower than the first pair of transformers. A cavity part 6a pierces through toward the axis at the center of a rotary shaft 6. Then the transformer 14 attached to a rotary member 8 is connected to its corresponding magnetic head by a wiring 12 passing through the part 6a.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a magnetic recording and reproducing device (including one that only plays) such as a video tape recorder (VTR), which has a one-rotation head, which is pulled out from a cassette and wound at a predetermined angle. The invention relates to a guide drum for recording signals on or reproducing signals from a tape. In particular, it relates to a guide drum equipped with four or more rotating heads, such as a sequential recording method.

(Prior Art) FIG. 8 shows the structure of a conventional guide drum on which multiple heads are mounted.

31 is a fixed side guide drum, and this fixed side guide drum 31 has a rotary shaft 3 on which a rotary shaft 36 is rotatably supported by bearings 9 and 11 made of ball bearings.
A rotary base 37 is fixed to the rotary base 37, and a rotation side guide drum 32 is fixed to the rotary base 37. A head base 40 is fixed to the zero rotation side guide drum 32.

The head 4 is attached to the tip of the head base 40.

The rotary base 37 also has a rotating side rotary transformer 33 bonded to its tip surface.

A fixed-side rotary transformer 35 is attached to the fixed-side guide drum 31 at a position opposite to the rotating-side rotary transformer 33. Signals are transferred to and from the head 4 by this pair of rotary transformers 33 and 35. Rotating side rotary transformer 33. A number of channels (grooves) corresponding to the number of heads are formed in the fixed rotary transformer 35, and a coil 38 is wound around each channel. In this example, five channels of coil 38 are wound for four video heads and one rotary erase head. 42 is a spacer, in order to ensure gap accuracy between the fixed side rotary transformer 35 and the rotating side rotary transformer 33.
It is provided between the bearing 9 and the rotary base 37.

In conventional VH8 system and β system videotape recorders, the diameter of the guide drum is sufficiently large, and it is possible to easily arrange up to 5 channels (5 herads) with the structure shown in Figure 8. Ta. That is, if the diameters of the stationary guide drum 31 and the rotating guide drum 32 are large, all the channels can be provided in the pair of rotary transformers 33 and 35, and furthermore, the dimensions d+o of the head base 40 can also be relatively Since the rotary base 37 is small, it is possible to extend the rotary base 37 from between the bearing 9 and the head base 40 to the position of the rotating side rotary transformer 33, and to secure a sufficient bonding surface T7.

In the rotary transformer 33.35, the distance between each channel must be a certain distance to avoid mutual influence, so as the number of channels increases, the difference between the inner diameter and the outer diameter of the rotary transformer 33.35 d3 becomes thicker.

1 On the other hand, as magnetic recording and reproducing devices become smaller and the diameter of the guide drum becomes smaller, for example for 8mm video, the outer diameter of the rotary transformer becomes smaller.
However, in reality, the diameters of the rotating shaft 36 and bearings 9 and 11 cannot be easily reduced from the viewpoint of rigidity and bearing strength. , Therefore, there are 5 in a pair of rotary transformers.
It becomes impossible to provide a channel coil. Also.

The size of the head base 40 cannot be made too small considering the accuracy of installation and the difficulty of adjustment. Therefore, the gap between the head base 40 and the bearing 9 becomes smaller, and it becomes extremely difficult to move the rotary base 37 downward from between them.

Furthermore, when attempting to downsize the magnetic recording/reproducing apparatus, the guide drum 44 partially enters into the opening 48 of the cassette 46 as shown in FIG. 9 when the cassette is attached. Although not shown in the figure, the cassette 46
The opening 48 is provided with a lid, and the lid is open when the cassette 46 is attached. therefore,
The height of the guide drum 44 is determined so that the upper surface of the guide drum 44 fits under the open lid.

Note that 52 is a supply reel, and 54 is a take-up reel.

On the other hand, if the entire guide drum 44 is lowered downward (perpendicular to the page), the tape must be bent sharply to the trajectory of the rotating head, which places undue force on the tape and makes it impossible to obtain clear image quality. Put it away.

(Purpose) The present invention allows four or more heads to be installed in a small-diameter guide drum, and allows the guide drum to partially fit into the opening of the cassette when the cassette is attached. It is an object of the present invention to provide a guide drum that can reduce the size of a magnetic recording and reproducing device without impairing image quality.

(Structure) In the guide drum of the present invention, two pairs of rotary transformers are provided, one pair of which is provided between the rotating guide drum and the stationary guide drum, and the other pair is provided between the rotating guide drum and the stationary guide drum. The rotary transformer is provided between the lower part of the fixed guide drum and a rotating member that is attached below the fixed guide drum to a rotating shaft that rotatably supports the rotating guide drum. Wiring between the rotary transformer and the corresponding magnetic head is conducted along the axis of rotation.

Examples will be specifically described below.

FIG. 1 shows an embodiment of a small-diameter guide drum according to the present invention. Figure 2 shows the rotating shaft in the same embodiment, Figure 3 shows the arrangement of four video heads and one rotating erasing head in the same embodiment, and Figure 4 shows the rotating guide drum. The mounting of the rotating erasing head and the rotating side rotary transformer is shown in part. In FIG. 1, the one-rotation erasing head portion shows the state cut at the line A-B in FIG. 4, and the other parts show the state cut at the line C-D in FIG.

In FIG. 1, a rotary shaft 6 is rotatably supported at the center of a stationary guide drum l fixed to a support member 1a by bearings 9 and 11 made up of ball bearings. A rotary base 7 is attached to the rotating shaft 6,
A rotating side guide drum 2 is attached to the rotary base 7.

In this embodiment, the rotary transformer is divided into two pairs. One rotary transformer pair consists of a rotating side rotary transformer 3 and a fixed side rotary transformer 5 that face each other below the head, and the other rotary transformer pair consists of rotating side rotary transformers that face each other further below the rotary transformer pair. It consists of a transformer 14 and a fixed rotary transformer 13.

A rotating member 8 that rotates together with the rotating shaft 6 is attached below the fixed guide drum 1 .

The rotating side rotary transformer 14 of the lower rotary transformer pair is mounted upward on the upper surface of the rotating member 8, and the fixed side rotary transformer 13 is attached to the fixed side guide drum 1 so as to face the rotating side rotary transformer 14. It is attached to the bottom of the.

A cavity 6a is formed in the center of the rotating shaft 6 and penetrates in the axial direction. The rotation-side rotary transformer 14 attached to the one-rotation member 8 and the corresponding magnetic head are connected by a wiring 12 passing through the cavity 6a of the rotation shaft 6.

The fixed rotary transformer 5 of the upper rotary transformer pair is mounted upward within the fixed guide drum l. The rotating side rotary transformer 3 corresponds to the fixed side rotary transformer 5.

As shown in FIG. 4, which will be described later, a ring-shaped C-shaped attachment with a portion cut out at a predetermined angle is bonded to the metal fitting 19. In this installation, the one-turn side rotary transformer 3 is attached to the rotating side guide drum 2 by fixing the metal fitting 19 to the rotating side guide drum 2.

FIG. 3 shows the arrangement of heads on the rotating guide drum 2. As shown in FIG. 4a to 4d are video heads, and 16 is a rotary erasing head. Further, 10a to 10d are head bases of video heads, and 15 is a head base of a rotary erasing head. As can be seen from this figure, there is almost no extra space on the end surface of the rotating side guide drum 2, and only holes or screw holes like 2a to 2e are made between the two helad bases. There is.

Since it is difficult to attach the rotation side rotary transformer 3 to the rotary base 7, the one rotation side rotary transformer 3 is attached to the rotation side guide drum 2. On the other hand, the video head bases loa to LOd have screws 17a-17.
However, it is difficult in terms of space to directly fix the spacing base 15 of the rotating erasing head 16 to the rotating guide drum 2.

FIG. 4 shows how the rotary erasing head 16 and the rotary transformer 3 are installed.

The helad base 15 of the rotary erasing head 16 is mounted and fixed to a ring 18. The ring 18 is attached to the video head hand base 10a, 1 of the rotating guide drum 2.
Screw holes 2a are provided between head bases 10C and 10d.

2b with screws 21a and 21b. moreover,
For attachment, the cylindrical protrusion 18a of the ring 18 abuts between the helad bases 10a and 10d, so that they can be stably fixed.

The rotating side rotary transformer 3 has a C-shaped mounting bracket 19.
It is fixed with adhesive. For installation, the metal fitting 19 is attached to the head bases 10a and 10 by its cylindrical projections 19a and 19c.
between 10c and 10d, and between 10d and 10a
Holes 2c and 2d made in the first rotation side guide drum 2 and in contact between the holes 2c and 2d.

The portion 2c is fixed by screws 22a, 22b, and 22c.

The vicinity of the rotary erasing head 16 is attached to the opening of the metal fitting 19, and the coils 23a to 23d of the rotary transformer 3 on the rotary side are pulled out from this part and attached to the relay board 20 glued to the back surface of the rotary transformer 3 on the rotary side. It is wired. These lead lines are connected to the video heads 4b and 4c on both sides of the rotary erasing head 16 among the four video heads.
is wired to. Wiring for the three channels of the rotating erasing head 16 and the video heads 4a and 4d is pulled out above the rotating guide drum 2 through holes 24a to 24f (see FIG. 3) made in the rotating guide drum 2, and the wiring 1
2, it is connected to a rotation-side rotary transformer 14 attached to the lower rotation member 8 through a hollow portion 6a at the center of the rotation shaft 6.

In this embodiment, when recording on the tape by winding the tape around the guide drums 2 and 3, the fixed rotary transformer 5 of the rotary transformer pair 3, 5, 13, 14 is used.
, 13, the recording signals are supplied to the video heads 4a to 4d via the rotating side rotary transformers 3 and 14. When erasing recorded information on a tape, the rotary erasing head 1 is passed from the fixed rotary transformer 13 of the rotary transformer pair 13° 14 to the rotating rotary transformer 14 in the same manner.
6 is supplied with an erase signal. At this time, signals are supplied from the lower rotary transformer 14 to the video heads 4a, 4d and the rotary erasing head 16 via the wiring 12 passing through the cavity 6a of the one-rotation shaft 6.

Also, when playing back signals recorded on tape,
Rotary transformer pair 3゜5.13.1
A reproduced signal is taken out from the rotating rotary transformer 3° 14 of No. 4 through the fixed rotary transformers 5 and 13. At this time as well, signals are supplied to the rotary transformer 14 on the lower side of the video heads 4a, 4d and the rotary erasing head 16 via the wiring 12 passing through the cavity 6a of the rotary shaft 6.

FIG. 5 shows the rotating shaft 25 in another embodiment.

This rotating shaft 25 is provided with grooves 25a to 25c in the axial direction. Wiring 12 connecting between the rotary transformer 14 attached to the rotating member 8 and the corresponding magnetic head is provided in the grooves 25a to 25c of the rotating shaft 25.

FIG. 6 shows a rotating shaft 25 in yet another embodiment.

The rotating shaft 26 is made of ceramic, which is a non-conductive material, and the outer surface of the rotating shaft 26 is provided with striped conductive bands 26a, 26b, . . . made of a conductive material in the axial direction. It is formed. These conductive band parts 26g, 26b,...
... plays the role of the wiring 12 in FIG.

In addition, there is a printed circuit board 2 on the top surface of the guide drum 2 on the one-rotation side.
7 can be installed. The rotating shaft 26 is inserted into the hole 28 in the center of the printed circuit board 27, and the conductive part 2 of the printed circuit board 27
7a, 27b, . . . and the conductive band portion 2 of the rotating shaft 26
13a, 261).

......contacts, and the rotating shaft 26 and the printed circuit board 2
7 becomes one. Also, although it is not shown in the figure.

Is there conductivity below the rotating shaft 26? F section 26a, 26b.

A printed circuit board similar to the printer 1 and the circuit board 27 is provided for exchanging signals. 29 is an insulating pipe, and this pipe 29 is inserted into the bearing 9 (11) of the ball bearing.
The rotary shaft 26 is arranged to fit inside.

(Effects) According to the present invention, it is possible to mount a large number of heads even on an extremely small-diameter guide drum, and the set can be made smaller, lighter, and more functional.

For example, the diameter of the guide drum is 74°487 in the β method.
mm, 62 mm for VHS format, and 40 mm for 8 mm video. For example, if you change this to a sequential recording system with four video heads, the diameter of the guide drum will be reduced to 2/2.
It can be reduced to 3. In the case of a conventional guide drum equipped with only one pair of rotary transformers, β method or V
) With the IS system, it is possible to use a sequential recording system, but when it comes to 8mm video, the diameter of the guide drum is too small, making it difficult.

Therefore, in the present invention, since the rotary 1 Herance is divided into two pairs, a sequential recording method is possible even for 8 mm video. In that case, the guide drum diameter can be reduced to 26.667 mm.

Further, according to the present invention, one pair of rotary transformers is provided between the rotating part guide drum and the stationary guide drum, and the other pair of rotary transformers is provided below the stationary guide drum. , the upper surface of the guide drum (in this case, the upper surface of the second rotation side guide drum 2) with the cassette 1-46 installed as shown in FIG.
can be lower than the lid 46a of the cassette 46.

Therefore, when the cassette is attached, the guide drum can be partially inserted into the openings of the cassettes 1 to 46 as shown in FIG. 9, thereby further contributing to miniaturization of the magnetic recording/reproducing apparatus.

As is clear from FIG. 7, the guide drum 2,
3, the position at which the tape is wound is not lowered, so no excessive force is applied to the tape, and the image quality does not deteriorate.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a perspective view showing the rotating shaft portion in the same embodiment, and Fig. 3 is the arrangement of the video head and the rotary erasing head on the end surface of the rotating guide drum. FIG. 4 is an exploded perspective view showing the rotating side guide drum, rotary erasing head, and rotary transformer; FIG. 5 is a perspective view showing the rotating shaft portion in another embodiment; FIG. 6 is a further example. FIG. 7 is a front sectional view showing the height positional relationship between the guide drum and the cassette in the embodiment, FIG. 8 is a sectional view showing the conventional guide drum l-, FIG. 9 is a plan view showing the positional relationship between the guide drum and the cassette when the cassette is attached. In addition. In Fig. 1, the head portion after rotation d1 is A- in Fig. 4.
It shows the state cut at line B, and the other parts show the state cut at line C-D. ■...Fixed side guide drum, 2...Rotating side guide drum, 3.14...Rotating side rotary transformer, 5.1
3...Fixed side rotary transformer, 4a to 4d.
...Video Head, 6.25.26...
Rotating shaft, 6a... Cavity, 8... Rotating member, 16... Rotating erasing head. 25a to 25c...Groove, 26a, 26b,...... Conductive band portion.

Claims (4)

[Claims] (1) A tape is wound helically at a predetermined angle around a guide drum having at least four or more rotating magnetic heads;
A magnetic recording and reproducing device that records signals on the tape or reproduces signals from the tape is provided with two pairs of rotary transformers, one of which is connected to a rotating guide drum and a stationary guide drum. The other pair of rotary transformers are installed between the lower part of the fixed guide drum and the rotary shaft that rotatably supports the rotating guide drum. A tape guide drum, characterized in that wiring between a rotary transformer provided on the rotating member and a corresponding magnetic head is provided along the rotating shaft. (2) A hollow section is provided in the center of the rotating shaft passing through in the axial direction, and wiring between the rotary transformer of the rotating member and the magnetic head is conducted through the hollow section. Tape guide drum described in . (3) A groove is provided in the side surface of the rotating shaft in the axial direction, and wiring between the rotary transformer of the rotating member and the magnetic head is conducted through the groove.
Tape guide drum as described in section. (4) The rotating shaft is made of a non-conductive material, and a plurality of conductive strips are formed in the axial direction on the side surface of the rotating shaft, and the rotary transformer of the rotating member and the magnetic head are connected to each other. 2. The tape guide drum according to claim 1, wherein wiring between the conductive bands is provided by the conductive band portion.